1. Field of the Invention
The present invention relates to a pair of trousers and particularly to such trousers which has creases, or crease lines on the top of the creases, which have excellent durability and are maintained sufficiently neat for a long time of use.
2. Related Art Statement
Generally, a pair of trousers has creases, or crease lines on the top of the creases, which are set by, e.g., steaming in at least the front and rear halves of each of the two leg coverings thereof. The creases or crease lines ensure that a wearer can always fold the trousers in the same fashion, thereby preventing the trousers from having undesirable wrinkles and/or becoming out of shape. These are technical advantages with the creases or crease lines set in the trousers. Additionally, the creases or crease lines give a straight silhouette to the trousers when the trousers are being worn on the wearer, thereby improving the visual appearance of the trousers. This is an aesthetic advantage with the creases or crease lines.
However, since the creases or crease lines are created simply by folding the fabric of the trousers, they "erase" little by little as the trousers is worn again and again. Specifically, while the trousers are worn on the wearer, tensile forces are exerted to the creases or crease lines in various directions because of physical motions of the wearer. Some of the tensile forces are exerted to the creases in directions in which to unfold or open the creases and thereby "erase" the crease lines on the top of the creases.
For keeping the creases or crease lines sufficiently neat in the trousers, it has conventionally been practiced to frequently iron the trousers at home. However, the ironing of the trousers is very cumbersome and time-consuming and furthermore it may deteriorate the fabric of the trousers.
In the above-described background, there have been various proposals to keep the creases in shape or the crease lines sufficiently neat in the trousers for a long period of use, without needing to frequently iron the trousers, and some of those proposals have been reduced to practice. One of such proposals is to sew trousers using a fabric produced by weaving a yarn made of wool mixed with polyester fiber. In this case, by utilizing the thermal plasticity of the polyester fiber, durable creases or crease lines are thermally set in the trousers. Meanwhile, in the case of trousers made purely of wool, the "CSIRO-set" process has generally been employed. In this process, an appropriate chemical agent or agents is/are applied to, or sprayed toward, the back or inner surfaces of creases and subsequently the creases are subjected to steaming, so as to improve the durability of the creases set in the wool trousers.
However, none of the known proposals has solved the above-mentioned problem to a satisfactory extent because the creases or crease lines set in the trousers according to any of the proposals are not effectively prevented from opening widely due to the tensile forces exerted thereto by the physical motions of the wearer while the trousers are worn on the wearer. Additionally, since the fabric used for sewing the trousers is produced by weaving warps and wefts, it has the property of restoring the creases to their basic forms, i.e., flat forms. For those reasons, it is very difficult to keep the creases in shape or the crease lines sufficiently neat in the trousers for a long time of use.
Stated differently, the creases or crease lines set in the trousers according to the conventional processes "erase" little by little during continued wearing of the trousers. The conventional processes suffer from additional disadvantages. First, those proposals are not versatile with respect to sorts of fabrics or sorts of yarns used for producing the fabrics, that is, are limited to specified fabrics or yarns. Second, in the case where the "CSIRO-set" process is employed for setting creases or crease lines in trousers, the overall production process is complicated because of use of one or more chemical agents. Additionally, some of those chemical agents react with a dye used for dying the fabric of the trousers, thereby discoloring the trousers. Thus, the use of the conventional process is limited to such fabrics dyed using specific dyes.
Meanwhile, it could be said that connecting, by stitching with thread, between two side portions on both sides of a crease line in trousers over the entire length of the side portions will prevent the crease line from opening widely due to the tensile forces exerted thereto. In this case, however, the stitches sewn into the side portions are exposed on the outside surface of the trousers, thereby worsening the outside appearance of the trousers and accordingly reducing the commercial value of the trousers. Thus, this method is not satisfactory, either.